The process of iontophoresis was described by LeDuc in 1908 and has since found commercial use in the delivery of ionically charged therapeutic agent molecules such as pilocarpine, lidocaine and dexamethasone. In this delivery method, ions are carried into the skin by an electrical current that is supplied by a positive and negative electrode. Positive ions are carried away from the positive anode, while negative ions are carried away from the negative cathode.
Earlier, and some present, iontophoretic devices have been typically constructed of two electrodes attached by adhesive materials to a patient, each connected by a wire to a remote power supply. A recent publication has indicated that sumatriptan can be transdermally transported effectively using iontophoresis (Femenia-Font et al, J. Pharm Sci 94, 2183-2186, 2005). In this study, iontophoretic transport of sumatriptan was found to be at a rate 385 fold higher than passive transport.